Re: [ANNOUNCE][CFT] kexec for v2.5.48 && kexec-tools-1.7 -- Success Story!

Eric W. Biederman
2002-11-20T09:10:52Z

Suparna Bhattacharya <suparna@in.ibm.com> writes:

> On Mon, Nov 18, 2002 at 05:10:38PM -0800, Andy Pfiffer wrote:
> > On Mon, 2002-11-18 at 00:53, Eric W. Biederman wrote:
> > > kexec is a set of systems call that allows you to load another kernel
> > > from the currently executing Linux kernel. The current implementation
> > > has only been tested, and had the kinks worked out on x86, but the
> > > generic code should work on any architecture.
> >
> > Great News, Eric. For the first time *ever* I got a kexec reboot to
> > work on my most troublesome machine (see below).
>
> Same here - preloading the new kernel and issuing kexec -e after
> init 1 works on the troublesome SMP system I'd earlier been sending
> you earlier. Bootimg used to work on this setup, so bypassing the
> bios calls had the expected effect.
>
> If I issue the call earlier though, it runs into trouble with aic7xxx
> reporting interrupts during setup. Guess you know why we are looking
> at that case - eventually need to be able to transition directly at dump
> time without a chance to go through user-space shutdown ...

The needed hooks are there. You can make certain an appropriate
->shutdown()/reboot_notifier method is present, or you can fix the driver
so it can initialize the device from any random state.

I really don't know what kinds of failures you hope to recover
from with the kexec on panic code, so I really can't comment on
how well things will work. There will always be a set of failures
that are non-recoverable, but that doesn't mean there isn't a useful
subset. Anyway there is certainly plenty of material for you to
experiment with and see what works usefully in practice.

Eric